Is paste mask layer, both top and bottom layer, necessary for THT components?

I know the paste mask layer is also called the stencil layer. It's only used for assembly. I want to know if the paste mask layer (both top and bottom layer) is necessary for through hole components. For SMD components I know the paste mask layer is required to solder the components. Is it necessary for through hole components?

No. Paste mask is normally used only for reflowing surface mount components, while the through hole components are soldered either manually or by wave solder bath at a later stage.

If you have through hole parts and the surface mount components on the bottom side, the paste mask stencil is not required, as the parts will all be soldered at once in a wave solder bath. This process requires you to generate a glue dot coordinates file, which will be used to place a dot of glue under the surface mount component and that will keep the part in place during the soldering process.

If the only through hole parts in the PCB were the connectors, it is also possible to reflow through hole components with solder paste. That requires some tweaking to get the right pad size and stencil opening. All we need to do is to have a larger pad on the top side, so that there was enough paste on the pad to wick down the hole and ensure a solid solder joint.

Read More: THT PCB Assembly

#PCB Assembly

Picture of Oliver Smith

Oliver Smith

Oliver is an experienced electronics engineer skilled in PCB design, analog circuits, embedded systems, and prototyping. His deep knowledge spans schematic capture, firmware coding, simulation, layout, testing, and troubleshooting. Oliver excels at taking projects from concept to mass production using his electrical design talents and mechanical aptitude.
Picture of Oliver Smith

Oliver Smith

Oliver is an experienced electronics engineer skilled in PCB design, analog circuits, embedded systems, and prototyping. His deep knowledge spans schematic capture, firmware coding, simulation, layout, testing, and troubleshooting. Oliver excels at taking projects from concept to mass production using his electrical design talents and mechanical aptitude.

What Others Are Asking

Can I design SMD elements on the back of THT?

I’m designing a PCB right now and found out I can save a lot of space using the back of THT elements. Is it legit to design like that? Are there any problems that might occur? 

Why aren’t components in DIP package shipped with straight pins?

I’ve noticed that all DIP packaged devices have pins which are at an angle other than 90∘ and need to be bent so that the angle is right for insertion into holes on the PCB or wherever. Is there any reason other than tradition for that? 

Read Detailed Advice From Blog Articles

Will Li

SMD Soldering: A Step-By-Step Guide

SMD soldering refers to the process of soldering surface mount electronic components to printed circuit boards. As electronic devices and PCBs have gotten progressively smaller,

Why Choose PCB Assembly in China
Will Li

Why Choose PCB Assembly in China?

Printed circuit board (PCB) assembly is an essential step in electronics manufacturing. It involves soldering and assembling electronic components onto a bare PCB board to create a functional

A Complete Guide to PCB Mounting Holes
Will Li

A Complete Guide to PCB Mounting Holes

What Are PCB Mounting Holes? PCB mounting holes refer to the holes that are drilled through the printed circuit board (PCB), so the board can

Scroll to Top